1. Field of the Invention
The present invention generally relates to a video printer for hard-copying a video signal. More particularly, the invention is concerned with a video printer for printing out as a hard copy a memory picture stored in a memory in the form of video data while overlaying thereon image(s) of characters, graphics and/or other picture(s).
2. Description of the Related Art
The video printer known heretofore is implemented in such a structure in which a sub-memory is provided in addition to a main memory, wherein original picture data is stored in the main memory with image data for the character(s), graphic pattern(s) and/or other picture(s) to be overlaid being stored in the sub-memory, and a picture resulting from synthesization of the original picture with the image(s) to be overlaid is once again stored in the main memory and thereafter read out to be printed out as a hard copy, as is disclosed in Japanese Patent Publication No. 62-42,428 (1987). With the hitherto known structure of the video printer, the original image (picture or video) data stored initially in the main memory is erased when the synthesized video or image data is stored in the main memory. Further, it is impossible to erase or cancel the overlay image(s) from the synthesized picture once stored in the main memory.
With the prior art technique mentioned above, it is certainly possible to erase a region of the original picture to be overlaid and display the region in one color, e.g. in black. However, the prior art video printer can not realize a white/black reversal function for erasing the original picture by coloring it in black except for the region where the overlay image is to be inlaid so that the original picture may appear as the background. Further, the prior art video printer can realize neither the function of displaying the original picture in a half-tone over a region to be overlaid nor a multi-synthesizing function for synthesizing selectively a plurality of words or character strings, graphic patterns and/or others.